Creatinine is a product of muscle metabolism in the body and is a very important indicator of kidney function. Elevated creatinine is often seen in patients with renal insufficiency: first, common causes such as acute glomerulonephritis patients, there will be a transient creatinine elevation, but most patients with acute glomerulonephritis have a tendency to heal themselves, and creatinine will normalize with the recovery of the disease process. The second common cause is acute renal failure, such as post-renal factors caused by obstruction of the urinary system, or pre-renal factors caused by shock, gastrointestinal bleeding, or severe burns, can lead to acute renal failure, as well as conditions such as tubular necrosis, which can lead to renal acute renal failure can lead to elevated creatinine. Finally, various causes can lead to chronic renal failure, which in turn causes an increase in blood creatinine. In clinical practice, the causes of chronic renal failure are mainly seen in chronic glomerulonephritis, hypertensive nephropathy, diabetic nephropathy and other conditions.